to_i

static VALUE
BigDecimal_to_i(VALUE self)
{
    ENTER(5);
    S_LONG e,nf;
    Real *p;

    GUARD_OBJ(p,GetVpValue(self,1));
    BigDecimal_check_num(p);

    e = VpExponent10(p);
    if(e<=0) return INT2FIX(0);
    nf = VpBaseFig();
    if(e<=nf) {
        e = VpGetSign(p)*p->frac[0];
        return INT2FIX(e);
    }
    else {
        VALUE a = BigDecimal_split(self);
        VALUE digits = RARRAY_PTR(a)[1];
        VALUE numerator = rb_funcall(digits, rb_intern("to_i"), 0);
        S_LONG dpower = e - RSTRING_LEN(digits);

        if (VpGetSign(p) < 0) {
            numerator = rb_funcall(numerator, '*', 1, INT2FIX(-1));
        }
        if (dpower < 0) {
            return rb_funcall(numerator, rb_intern("div"), 1,
                              rb_funcall(INT2FIX(10), rb_intern("**"), 1,
                                         INT2FIX(-dpower)));
        }
        return rb_funcall(numerator, '*', 1,
                          rb_funcall(INT2FIX(10), rb_intern("**"), 1,
                                     INT2FIX(dpower)));
    }
}